Warning : because of the psycho-acoustic tricks used in lossy codecs, spectrogram-based comparisons, signal cancellation, or artifacts amplification (SoundExpert tests) are not suited for the evaluation of the audio performance of these codecs.

Study, including blind tests, on the sound of CD pressings : The numerically-Identical CD mystery Ian Dennis, Julian Dunn and Doug Carson.>> To put in balance against the "jitter theory", presented by Bob Katz in order to explain audible differences between originals and copies, or between digital drives; and with Bruno Putzeys' indications, who measured distortion in the analog output of a CD Player.